U.S. patent number 6,712,877 [Application Number 10/228,134] was granted by the patent office on 2004-03-30 for oxygen concentrator system.
This patent grant is currently assigned to Litton Systems, Inc.. Invention is credited to Lyle Berkenbosch, Gary Byrd, Tuan Q. Cao, Craig Schledewitz.
United States Patent |
6,712,877 |
Cao , et al. |
March 30, 2004 |
Oxygen concentrator system
Abstract
An oxygen concentrator system includes at least one oxygen
concentrator sub-system and a plenum subsystem. The at least one
oxygen concentrator sub-system produces oxygen-enriched air which
is outputted to both the oxygen concentrator system output and to a
plenum chamber within the plenum subsystem. The plenum chamber is
trickle charged with the oxygen-enriched air when the at least one
oxygen concentrator sub-system produces an excess amount of
oxygen-enriched air. Should the demand for oxygen-enriched air
exceed the capability of the at least one oxygen concentrator
sub-system, additional oxygen-enriched air is provided by the
plenum chamber until such time that the capability of the at least
one oxygen concentrator sub-system exceeds the demand of
oxygen-enriched air. At that time, oxygen-enriched air is no longer
provided by the plenum chamber but rather the plenum chamber is
again trickle charged.
Inventors: |
Cao; Tuan Q. (Davenport,
IA), Byrd; Gary (Donahue, IA), Berkenbosch; Lyle
(Bettendorf, IA), Schledewitz; Craig (Davenport, IA) |
Assignee: |
Litton Systems, Inc. (Los
Angeles, CA)
|
Family
ID: |
31495335 |
Appl.
No.: |
10/228,134 |
Filed: |
August 27, 2002 |
Current U.S.
Class: |
95/10; 95/130;
95/19; 95/8; 95/96; 96/111; 96/113; 96/130; 96/144 |
Current CPC
Class: |
B01D
53/047 (20130101); B01D 53/261 (20130101); B01D
2253/102 (20130101); B01D 2253/104 (20130101); B01D
2253/108 (20130101); B01D 2256/12 (20130101); B01D
2257/80 (20130101); B01D 2257/90 (20130101); B01D
2259/40003 (20130101); B01D 2259/40009 (20130101); B01D
2259/402 (20130101); B01D 2259/404 (20130101) |
Current International
Class: |
B01D
53/047 (20060101); B01D 53/04 (20060101); B01D
053/053 () |
Field of
Search: |
;95/8,10-12,19,21,22,96-98,100-105,117-119,122,130
;96/110,111,113-115,130,143,144 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Spitzer; Robert H.
Attorney, Agent or Firm: Lowe Hauptman Gilman & Berner,
LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is related to co-pending application,
entitled "OXYGEN CONCENTRATOR SYSTEM WITH ALTITUDE COMPENSATION",
Ser. No. 10/227,806, filed Aug. 27, 2002.
Claims
What is claimed is:
1. A method of increasing oxygen concentration, the method
comprising: receiving supply air from a system air inlet at an
input of at least one oxygen concentrator subsystem and outputting
oxygen enriched air to at least one system outlet; receiving supply
air from a system air inlet at an input of a medical air sub-system
and outputting medical grade air to at least one system medical
grade air outlet; and selectively enabling oxygen-enriched air to
flow from the at least one oxygen concentrator subsystem to a
plenum.
2. The method of claim 1, wherein receiving supply air in at least
one oxygen concentrator subsystem and outputting oxygen-enriched
air to at least one system outlet comprises receiving supply air in
a pair of oxygen PSA (Pressure Swing Adsorption) beds.
3. The method of claim 1, further comprising metering and
controlling the flow of oxygen enriched air between the at least
one oxygen concentrator subsystem and the plenum and allowing the
flow from the at least one oxygen concentrator subsystem to the
plenum.
4. The method of claim 1, further comprising controlling the oxygen
enriched air pressure between the plenum and the at least one
system outlet.
5. The method of claim 1, further comprising controlling the air
pressure between the system air inlet and the at least one oxygen
concentrator subsystem.
6. The method of claim 1, further comprising filtering air flowing
between the system air inlet and the at least one oxygen
concentrator subsystem.
7. The method of claim 6, further comprising exhausting waste
products resulting from filtering air flowing between the system
air inlet and the at least one oxygen concentrator subsystem.
8. The method of claim 1, wherein filtering air flowing between the
system air inlet and the at least one oxygen concentrator subsystem
comprises at least one of particulate filtering and water vapor
filtering.
9. The method of claim 1, further comprising exhausting waste
products from the at least one oxygen concentrator subsystem.
10. The method of claim 1, further comprising selectively dumping
waste products from the at least one oxygen concentrator subsystem
and the plenum.
11. The method of claim 1, further comprising allowing oxygen
enriched air to flow only between the plenum and the at least one
system outlet.
12. The method of claim 1, further comprising regulating the flow
of air between the medical air subsystem and the at least one
system medical grade air outlet.
13. The method of claim 1, further comprising measuring the oxygen
concentration of the oxygen-enriched air at the at least one system
outlet with an oxygen sensor.
14. The method of claim 13, further comprising regulating the
absolute pressure of the oxygen-enriched air flowing to the oxygen
sensor to control the air pressure thereof so as to be independent
of altitude.
15. The method of claim 1, further comprising detecting a carbon
monoxide concentration and a dew point of the medical grade air at
the at least one system medical grade air outlet.
16. The method of claim 1, further comprising trickle charging the
plenum upon the at least one oxygen concentrator sub-system air
pressure being greater than the plenum air pressure.
17. The method of claim 1, further comprising selectively bypassing
the plenum to enable oxygen enriched air to flow from the at least
one oxygen concentrator system to the at least one system
outlet.
18. An oxygen concentrator system comprising: a system air inlet to
receive supply air; at least one system outlet to output
oxygen-enriched air; at least one system outlet to output medical
grade air; a medical air sub-system to receive supply air from the
system air inlet and to supply medical grade air to the at least
one system medical grade air outlet; at least one oxygen
concentrator subsystem including an input to receive supply air
from the system air inlet and an output to output medical grade air
to the at least one system outlet; and a plenum and a plenum
charging system located between the output of the at least one
oxygen concentrator subsystem and the at least one system outlet,
the plenum charging system selectively enabling oxygen-enriched air
to flow from the at least one oxygen concentrator subsystem to the
plenum.
19. The system of claim 18, wherein the at least one oxygen
concentrator subsystem comprises a pair of oxygen PSA (Pressure
Swing Adsorption) beds.
20. The system of claim 18, wherein the plenum charging system
comprises a charging check valve and a charging control orifice and
a flow control regulator connected serially together to meter and
to control the flow of oxygen enriched air between the at least one
oxygen concentrator subsystem and the plenum and to allow the flow
of oxygen enriched air only from the at least one oxygen
concentrator subsystem to the plenum.
21. The system of claim 20, wherein the charging check valve and
charging control orifice and flow control regulator allow the flow
of air from the at least one oxygen concentrator sub-system to the
plenum to trickle charge the plenum upon the at least one oxygen
concentrator sub-system air pressure being greater than the plenum
air pressure.
22. The system of claim 18, further comprising at least one
pressure regulator located between the plenum and the at least one
system outlet to control the oxygen enriched air pressure there
through.
23. The system of claim 18, further comprising an inlet pressure
regulator located between the system air inlet and the at least one
oxygen concentrator subsystem to control the air pressure
therethrough.
24. The system of claim 18, further comprising an inlet filter
assembly located between the system air inlet and the at least one
oxygen concentrator subsystem.
25. The system of claim 24, wherein the inlet filter assembly
comprises at least one of a particulate filter and a water vapor
filter.
26. The system of claim 24, further comprising a system exhaust to
exhaust waste products from the inlet filter assembly.
27. The system of claim 18, further comprising a system exhaust to
exhaust waste products from the at least one oxygen concentrator
subsystem.
28. The system of claim 27, further comprising a dump valve and a
dump orifice located between the at least one system outlet and the
system exhaust to selectively dump waste products from the at least
one oxygen concentrator subsystem and the plenum.
29. The system of claim 27, further comprising a muffler located
between the system exhaust and the at least one oxygen concentrator
subsystem to muffle noise emanating therefrom.
30. The system of claim 18, further comprising a discharging check
valve located between the plenum and the at least one system outlet
to allow air flow only between the plenum and the at least one
system outlet.
31. The system of claim 18, further comprising a medical grade air
regulator located between the medical air sub-system and the at
least one system medical grade air outlet to regulate the air
pressure output therefrom.
32. The system of claim 18, further comprising an oxygen sensor
selectively connected to the at least one system outlet to measure
the oxygen concentration of the oxygen-enriched air.
33. The system of claim 32, further comprising an absolute pressure
regulator connected to the oxygen sensor to control the air
pressure thereof so as to be independent of altitude.
34. The system of claim 18, further comprising at least one of a
carbon monoxide detector and a dew point detector to respectively
detect the carbon monoxide concentration and the dew point of the
medical grade air.
35. The system of claim 18, further comprising a plenum bypass
valve to selectively bypass the plenum so as to enable oxygen
enriched air to flow from the at least one oxygen concentrator
subsystem to the at least one system outlet.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to oxygen concentrator systems, and
more particularly, to a patient ventilator oxygen concentrator
system in which a plenum is used to provide a sufficient flow of
oxygen-enriched product under various conditions. The plenum may be
selectively bypassed to improve the transient response of the
concentrator system. Furthermore, the plenum may be trickle charged
when needed so as to maintain the reserve capacity of the
plenum.
2. Description of the Related Art
Many medical applications exist that require either oxygen-enriched
product or medical grade air. Both are widely used in respiratory
care treatments, for example. Furthermore, both oxygen-enriched
product and medical grade air are used to power various
pneumatically driven medical devices.
Hospitals and other medical care facilities have a need for both
oxygen-enriched product and medical grade air. In military
hospitals and in hospitals in Europe, for example, these needs may
be met by using oxygen concentration systems to provide
oxygen-enriched product and by using a filtration system for
providing medical grade air. On the other hand, hospitals and other
medical care facilities in the United States often use
high-pressure gas systems or liquid oxygen to gaseous conversion
systems to provide oxygen-enriched product.
Commonly used oxygen concentration systems often employ a pressure
swing adsorption (PSA) process to remove nitrogen from a given
volume of air to produce oxygen-enriched product. Such a process is
disclosed in U.S. Pat. No. 4,948,391 to Noguchi and this patent is
incorporated herein by reference in its entirety.
In such oxygen concentration systems, for example, as the plenum
pressure is increased, the product flow output, that is, the
oxygen-enriched product output, is decreased and the oxygen
concentration increased. Accordingly, at low plenum pressures, the
oxygen concentration of the oxygen-enriched product output may be
insufficient.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an oxygen
concentrator system which utilizes at least one oxygen concentrator
subsystem and a plenum to provide an oxygen-enriched product
output.
It is a further object of the present invention to provide an
oxygen concentrator system as above and including a plenum charging
system to meter and to control the flow of product between the at
least one oxygen concentrator subsystem and the plenum and to allow
the flow of oxygen product only from the at least one oxygen
concentrator subsystem to the plenum. The plenum is trickle charged
when needed to maintain its reserve capacity.
It is another object of the present invention to provide an oxygen
concentrator system as above and further including a discharging
check valve to selectively allow the plenum reserve capacity to
flow out only during a high demand oxygen flow.
It is yet another object of the present invention to provide an
oxygen concentrator system as above and further including a plenum
bypass valve to make the transient response faster and to avoid
overdrawing the at least one oxygen concentrator subsystem so as to
keep the oxygen concentration of the oxygen-enriched air above a
predetermined minimum value.
These and other objects of the present invention are achieved by an
oxygen concentrator system comprising: a system air inlet to
receive supply air; at least one system outlet to output
oxygen-enriched product; at least one oxygen concentrator subsystem
including an input to receive supply air from the system air inlet
and an output to output oxygen-enriched product to the at least one
system outlet; a plenum and a plenum charging system located
between the output of the at least one oxygen concentrator
subsystem and the at least one system outlet, the plenum charging
system selectively enabling oxygen-enriched product to flow from
the at least one oxygen concentrator subsystem to the plenum; and
an optional plenum bypass valve to selectively bypass the plenum so
as to enable oxygen-enriched air to flow from the at least one
oxygen concentrator subsystem to the at least one system
outlet.
The foregoing and other objects of the present invention are
achieved by a method of increasing oxygen concentration, the method
comprising: receiving supply air from a system air inlet at an
input of at least one oxygen concentrator subsystem and outputting
oxygen-enriched product to at least one system outlet; selectively
enabling oxygen-enriched air to flow from the at least one oxygen
concentrator subsystem to the plenum; and selectively bypassing the
plenum to enable oxygen-enriched product to flow from the at least
one oxygen concentrator system to the at least one system
outlet.
The foregoing and a better understanding of the present invention
will become apparent from the following detailed description of an
example embodiment and the claims when read in connection with the
accompanying drawings, all forming a part of the disclosure of this
invention. While the foregoing and following written and
illustrated disclosure focuses on disclosing an example embodiment
of the invention, it should be clearly understood that the same is
by way of illustration and example only and that the invention is
not limited thereto. This spirit and scope of the present invention
are limited only by the terms of the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The following represents brief descriptions of the drawings,
wherein:
FIGS. 1A-1D together form a pneumatic diagram of a patient
ventilator oxygen concentrator system in accordance with an example
embodiment of the present invention wherein FIG. 1 is divided into
four parts, including FIGS. 1A, 1B, 1C and 1D. FIG. 1A is the upper
left hand quadrant of FIG. 1; FIG. 1B is the upper right hand
quadrant of FIG. 1; FIG. 1C is the lower left hand quadrant of FIG.
1; and FIG. 1D is the lower right hand quadrant of FIG. 1.
FIGS. 2A and 2B are a simplified pneumatic diagram of the patient
ventilator oxygen concentrator system of FIGS. 1A-1D together.
FIG. 3 is a timing diagram illustrating the timing cycles for the
oxygen beds of FIGS. 1A-1D together.
FIG. 4 is a timing diagram illustrating the synchronization between
the oxygen beds and air beds of FIGS. 1A-1D together.
DETAILED DESCRIPTION
Before beginning a detailed description of the subject invention,
mention of the following is in order. When appropriate, like
reference numerals and characters may be used to designate
identical, corresponding, or similar components in differing
drawing figures. Furthermore, in the detailed description to
follow, example sizes/models/value/ranges may be given, although
the present invention is not limited thereto. Still furthermore,
any clock or timing signals in the drawing figures are not drawn to
scale but rather, exemplary and critical time values are mentioned
when appropriate. When specific details are set forth in order to
describe example embodiment of the invention, it should be apparent
to one skilled in the art that the invention can be practiced
without, or with variations of, these specific details. Lastly, it
should be apparent that differing combinations of hard-wired
control circuitry and software instructions may be used to
implement embodiments of the present invention, that is, the
present invention is not limited to any specific combination of
hardware and software.
An oxygen concentrator system in accordance with the present
invention provides a plenum which is used to provide a sufficient
flow of oxygen-enriched air under various conditions. The plenum
may be selectively bypassed to improve the transient response of
the concentrator system. Furthermore, the plenum may be trickle
charged when needed so as to maintain the reserve capacity of the
plenum.
A charging circuit is provided to trickle charge the plenum when
the output pressure of the oxygen PSA sub-systems is higher than
the plenum pressure, thereby maintaining the reserve capacity of
the plenum.
The plenum reserve capacity can be used to augment the oxygen PSA
sub-systems output when there is a high oxygen flow output
demand.
FIGS. 1A-1D together is a pneumatic diagram of a patient ventilator
oxygen concentrator system in accordance with an example embodiment
of the present invention and FIGS. 2A-2B together is a simplified
pneumatic diagram of the patient ventilator oxygen concentrator
system of FIGS. 1A-1D together. The following discussion refers
both to FIGS. 1A-1D together and FIGS. 2A-2B together.
As illustrated in FIGS. 1A-1D together, the oxygen concentrator
system 100 includes three main elements, namely, a plenum system
30, a front panel assembly 40, and a bed module 50. A fourth
element of the oxygen concentrator system 100 includes a
monitor/controller 200 and input/output electrical panel 210 having
switches and indicators and a display. For simplicity, the fourth
element of the oxygen concentrator system has been omitted from
FIGS. 1A-1D together but is illustrated in FIGS. 2A-2B
together.
As illustrated in FIG. 1, supply air is input into the plenum
system 30. Relief valve RV1 is provided to protect the system from
overpressure. Similarly, relief valves RV2-RV4 are also included in
the system to protect against overpressure. After passing through
filters FLTR1 and FLTR2, and pressure regulator REG1, the supply
air is fed to solenoid valves SV1, SV2, and SV7.
The three two-way solenoid valves SV1, SV7, and SV2 respectively
control the inputting of the supply air to the medical air modules
AIR-1 and AIR-2 and to the oxygen PSA modules O2-1 and O2-2, O2-3
and O2-4 of the bed module 50. Each of the medical air modules
AIR-1 and AIR-2 includes its own three-way solenoid valve SV12 and
SV13 which allows the supply air to selectively enter and exit
respective air beds 1 and 2.
Similarly, each of the oxygen and PSA modules O2-1 and O2-4
includes its own three-way solenoid valve SV9-SV12 which allows the
supply air to selectively enter oxygen beds 1-4. The other
connection of all of the three-way solenoids valves SV9-SV12 are
connected together to a muffler MUF whose output is connected to an
exhaust output of the plenum system 30. Orifices ORF5-ORF7 are
respectively disposed between oxygen beds 1 and 2 and between
oxygen beds 3 and 4 and between air beds 1 and 2. Check valves
CV1-CV6 are respectively connected to the air beds 1 and 2 and the
oxygen beds 1-4.
Supply air is provided to FLTR1 and FLTR2 which in turn is pressure
regulated by REG1 which is connected to inlet temperature switch
TSW1 and to low pressure warning and pressure switch PSW-3.
The output of air beds 1 and 2 are connected via check valves CV1
and CV2 to serially connected filters FLTR3 and FLTR4 whose output
is in turn connected via solenoid valve SV6 and regulator REG4 to a
medical air line which is connected to the front panel assembly 40.
A source of backup medical air, for example, a compressed air tank,
is connected to the solenoid valve SV6 so as to provide a
continuous source of medical air should the oxygen concentrator
system fail.
Various monitoring devices, such as: a carbon monoxide monitor 120
connected to the medical air line via the orifice ORF4 and having
an output connected to a vent, a dewpoint monitor 130 connected to
the medical air line, the relief valve RV2 connected to the monitor
air line, a pressure switch PSW2 for detecting a low-pressure in
the medical air line, and a gauge G3 located on the front panel
assembly 40 to indicate the actual medical air line pressure, have
been provided.
The medical air line is connected to a solenoid valve SV5 so as to
be selectively connected to an oxygen sensor 140 which includes a
regulator REG5 to control the pressure therethrough. The medical
air line is also connected to a manifold having 4 valves V5-V8
whose outputs are respectively connected to AIR OUT 1-4.
The outputs of oxygen beds 1 and 2 are connected together to
orifice ORF1 while the outputs of oxygen beds 3 and 4 are connected
together to orifice ORF2. The outputs of orifice ORF1 and orifice
ORF2 are connected together to the plenum 110 via regulator REG2
and filter FLTR5. The output of the plenum 110 is connected via
solenoid valve SV4 and regulator REG3 to an oxygen line on the
front panel assembly 40 and via a filter FLTR6 and regulator REG5
to a low-pressure oxygen line on the front panel assembly 40.
The oxygen line on the front panel assembly 40 is connected to a
manifold having four valves V1-V4 whose outputs are respectively
connected to O2 OUT 1-4. A gauge G2 is located on the front panel
assembly 40 and is connected to the oxygen line so as to indicate
the actual oxygen line pressure. A plenum pressure gauge G1 and a
pressure switch PSW4 as well as orifice ORF3 are also connected to
the output of the plenum 110.
The output of the orifice ORF3 is connected via solenoid valve SV3
and valve V9 to the exhaust of the system so as to allow the
purging of the contents of the plenum 110. A source of backup
oxygen, such as a tank of compressed oxygen, is connected to the
solenoid valve SV4 to provide a continuous source of oxygen should
the oxygen concentrator system fail. Low pressure warning switch
PSW1 and relief valves RV3 and RV4 are also provided.
Lastly, the low-pressure oxygen line is respectively connected via
check valves CV1 and CV2 to flow meters FLM1 and FLM2 whose outputs
are respectively connected to LOW P O2 OUT 1-2.
Referring to FIGS. 2A-2B together, which is a simplified pneumatic
diagram of the patient ventilator oxygen concentrator system of
FIGS. 1A-1D together, some elements have been consolidated for
simplicity and other elements, such as the relief valves, have not
been shown so as not to obscure the features of the system.
Similarly, other elements, such as the monitor/controller 200, were
not shown in FIGS. 1A-1D together but are shown in FIGS. 2A-2B
together.
The operation of the concentrator system illustrated in FIGS. 1 and
2 is as follows. Air is supplied to the supply air inlet where it
is received by the inlet pressure regulator and filter assembly
REG1, FLTR1 and FLTR2. The pressure regulator REG1 regulates the
air pressure of the air supplied to the air inlet so as to be at a
constant value, for example, 80 PSIG The filters FLTR1 and FLTR2
remove particulate matter and water which may be present in the air
supplied to the air inlet. A line labeled DRAIN is used to convey
the removed water to the EXHAUST via an element labeled EXHAUST SUM
which may be a manifold, for example. Dump valve SV3 is connected
to EXHAUST SUM via dump orifice DRF3 where the dump orifice is a
flow rate restriction device restricting the rate of flow of the
exhaust to be at an ambient pressure.
The oxygen PSA sub-systems 1 and 2 respectively include oxygen beds
1 and 2 and oxygen beds 3 and 4. Each bed comprises a molecular
sieve bed which generates an oxygen product gas by the
pressure-swing-adsorption method. Quantitatively, each subsystem
may be designed to generate up to 10 liters per minute of oxygen
product at an oxygen concentration of 93 +/-3%.
The medical air sub-system consists of air beds 1 and 2 which may
each include an activated alumina air dryer bed which operates in
the pressure-swing-adsorption mode, a micron filter to remove
particulates and an odor removal filter, such as activated
charcoal. Quantitatively, the medical grade air sub-system may be
designed to generate up to 150 liters per minute of medical air,
for example.
As illustrated in FIG. 3, oxygen beds 1-4 are each cycled between a
charging cycle and a flushing cycle. PSA beds typically have a
charging cycle equal to 55% of the total cycle time and a flushing
cycle equal to 45% of the total cycle time. As illustrated in FIG.
3, beds 1 and 2 have an overlap (OVL) and beds 3 and 4 also have an
overlap (OVL). As an example, the total cycle time may be on the
order of 12 seconds with the overlap time being on the order of 0.5
seconds. By having two sets of oxygen PSA sub-systems, it is
possible to operate one oxygen PSA sub-system when the demand for
oxygen is below a preset amount and to operate both PSA sub-systems
when the demand for oxygen exceeds the present amount.
In a similar fashion, air beds 1 and 2 also cycle between a
charging cycle and a flushing cycle. As an example, the total cycle
time for the air beds may be four times that of the oxygen beds.
Accordingly, the total cycle time may be on the order of 48 seconds
and the default overlap time may be on the order of 3 seconds with
the PSA time being 21 seconds.
FIG. 4 is a timing diagram illustrating the synchronization between
the air beds and the oxygen beds. While it is not absolutely
necessary for the sets of air beds and oxygen beds to be in
synchronization with each other, the synchronization therebetween
can simplify the monitor controller/200.
The monitor/controller 200, in conjunction with the input/output
panel 210, is used to activate and switch the various valves
utilized in the system. Furthermore, in conjunction with the carbon
monoxide sensor 120, dewpoint sensor 130 and oxygen sensor 140 and
self-test valve SV5, the monitor/controller monitors the oxygen
concentration in the oxygen product gas, as well as monitoring the
dewpoint level and carbon monoxide level and the oxygen
concentration in the medical grade air. Based on the status of the
system, as a monitored by the monitor/controller 200, status
indications may be displayed on the input/output panel 210
utilizing a digital display or LED indicators, for example.
Since the oxygen sensor 140 output varies with altitude, the
absolute pressure regulator REG5 is provided to keep the pressure
of the oxygen sensor's chamber at a relatively constant value, for
example, 16 PSIA so as to allow the system to operate at various
altitudes without requiring the recalibration of the oxygen sensor
140.
The muffler MUF has been provided to reduce the noise caused by the
exhausts from the oxygen PSA sub-systems 1 and 2 and the medical
air sub-system since it is common to utilize oxygen concentrator
systems in hospital environments requiring low noise levels.
Initially, during startup of the system, and particularly when
there is no pressure in the plenum 110, the monitor/controller 200
opens the dump valve SV3, that is, allows gas to flow therethrough,
and closes the plenum bypass valve BPV, that is, prevents gas from
flowing therethrough, so as to flush the plenum 110 of any residual
gas contained therein.
The oxygen PSA sub-systems 1 and 2 are then operated so as to
produce the output oxygen product which flows through the charging
check valves CV1-4 and charging control orifices ORF1 and ORF2 and
the flow control regulator REG2 into the plenum 110. The oxygen
concentration of the oxygen product leaving the plenum 110 is
measured by the oxygen sensor 140.
When the oxygen concentration exceeds a predetermined amount, for
example, 90%, as measured by the oxygen sensor 140, the dump valve
SV3 is opened so as to allow the oxygen product from the oxygen PSA
sub-systems 1 and 2 to charge the plenum 110 via a charging control
circuit including the charging check valves CV1-4, the charging
control orifices ORF1 and ORF2, and the flow control regulator
REG2. The charging control circuit limits the charging rate to a
level which is less than a maximum output from the oxygen PSA
sub-systems 1 and 2 when the plenum pressure is below the switch
point of the plenum pressure switch PSW4, for example, 65 PSIG, so
as not to overdraw the oxygen PSA sub-systems 1 and 2.
When the plenum pressure switch PSW4 changes state to indicate to
the monitor/controller 200 that the pressure at the output of the
plenum 110 is above its setpoint, the monitor/controller 200 opens
the plenum bypass valve BPV to allow the oxygen product to flow
directly to the various oxygen outlets. The direct flow of the
oxygen product to the oxygen outlets rather than flowing through
the plenum 110 enables the system to respond faster to transients
such as line pressure changes or output flow changes.
When the system is in a high oxygen flow mode, for example, a 65
liters per minute purge flow, the discharging check valve DCV opens
due to the pressure drop downstream of the check valve DCV to
discharge the plenum 110 and thereby allow the high-pressure purge.
The reserve capacity of the plenum 110 is mainly used for purging
for short periods of time, such as 18 seconds, for example. Upon
the completion of the purging, the charging control circuit trickle
charges the plenum 110 when the output pressure of PSA sub-systems
1 and 2 is higher than the plenum pressure. That is, excess
capacity of the PSA sub-systems 1 and 2 are used to recharge the
plenum to maintain its reserve capacity.
An oxygen concentrator system in accordance with the present
invention offers the following advantages:
The charging circuit trickle charges the plenum when the output
pressure of the oxygen PSA sub-systems 1 and 2 is higher than the
plenum pressure.
The discharging check valve allows the plenum reserve capacity to
be used to augment the oxygen PSA sub-systems 1 and 2 output when
there is a high oxygen flow output demand.
The plenum bypass valve makes the transient response faster by
allowing the output of the oxygen PSA sub-systems 1 and 2 to
directly flow to the oxygen concentrator system output ports.
The plenum pressure switch, in conjunction with the
monitor/controller, controls the plenum bypass valve to avoid
overdrawing the oxygen PSA sub-systems 1 and 2 so as to maintain
the oxygen concentration of the oxygen concentrator system output
above a predetermined minimum level.
The dump valve allows the plenum to be flushed upon being emptied
for long periods of time or when filled with air.
The dump orifice allows sufficient flow to flush the plenum and
allows sufficient back pressure to allow a flow through the oxygen
sensor to allow the oxygen sensor to monitor the oxygen
concentration during startup.
The self-test valve allows for the self-testing of the oxygen
sensor.
The oxygen sensor absolute pressure regulator enables the oxygen
sensor to operate at higher altitudes without recalibration.
Lastly, the exhausts sum allows excess water removed from the
supply air to be flushed out.
This concludes the description of the example embodiment. Although
the present invention has been described with reference to a number
of illustrative embodiments thereof, it should be understood that
numerous other modifications and embodiments can be devised by
those skilled in the art that will fall within the spirit and scope
of the principles of this invention. More particularly, reasonable
variations and modifications are possible in the component parts
and/or arrangements of the subject combination arrangements within
the scope of the foregoing disclosure, the drawings, and the
appended claims without departing from the spirit of the invention.
In addition to variations and modifications in the component parts
and/or arrangements, alternative uses will also be apparent to
those skilled in the art.
For example, the number of oxygen beds and oxygen PSA sub-systems
is not limited to the number shown in the illustrative embodiment.
Furthermore, the present invention is not limited to the exact
arrangement of solenoid valves, check valves, relief valves,
pressure switches, and pressure regulators shown in the
illustrative embodiment. Still furthermore, the bypass valve and
discharge check valve may be omitted in some configurations.
* * * * *